usb: dwc2: gadget: Correct dwc2_hsotg_ep_stop_xfr() function

Correct dwc2_hsotg_ep_stop_xfr() function to follow dwc2 programming
guide for setting NAK on specific endpoint, disabling it and flushing
corresponding FIFO.

Current code does not take into account whether core acts in shared or
dedicated FIFO mode, current endpoint is periodic or not. It does not
clear EPDISBLD interrupt after programming of DXEPCTL_EPDIS, does not
flush shared TX FIFO and tries to clear global out NAK in wrong manner
instead of setting DCTL_CGOUTNAK.
Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/gadget.c

@@ -3868,13 +3868,25 @@ static void dwc2_hsotg_ep_stop_xfr(struct dwc2_hsotg *hsotg,
 
 	dev_dbg(hsotg->dev, "%s: stopping transfer on %s\n", __func__,
 		hs_ep->name);
+
 	if (hs_ep->dir_in) {
+		if (hsotg->dedicated_fifos || hs_ep->periodic) {
 			__orr32(hsotg->regs + epctrl_reg, DXEPCTL_SNAK);
 			/* Wait for Nak effect */
 			if (dwc2_hsotg_wait_bit_set(hsotg, epint_reg,
 						    DXEPINT_INEPNAKEFF, 100))
 				dev_warn(hsotg->dev,
-				"%s: timeout DIEPINT.NAKEFF\n", __func__);
+					 "%s: timeout DIEPINT.NAKEFF\n",
+					 __func__);
+		} else {
+			__orr32(hsotg->regs + DCTL, DCTL_SGNPINNAK);
+			/* Wait for Nak effect */
+			if (dwc2_hsotg_wait_bit_set(hsotg, GINTSTS,
+						    GINTSTS_GINNAKEFF, 100))
+				dev_warn(hsotg->dev,
+					 "%s: timeout GINTSTS.GINNAKEFF\n",
+					 __func__);
+		}
 	} else {
 		if (!(dwc2_readl(hsotg->regs + GINTSTS) & GINTSTS_GOUTNAKEFF))
 			__orr32(hsotg->regs + DCTL, DCTL_SGOUTNAK);
@@ -3882,8 +3894,8 @@ static void dwc2_hsotg_ep_stop_xfr(struct dwc2_hsotg *hsotg,
 		/* Wait for global nak to take effect */
 		if (dwc2_hsotg_wait_bit_set(hsotg, GINTSTS,
 					    GINTSTS_GOUTNAKEFF, 100))
-			dev_warn(hsotg->dev,
-				"%s: timeout GINTSTS.GOUTNAKEFF\n", __func__);
+			dev_warn(hsotg->dev, "%s: timeout GINTSTS.GOUTNAKEFF\n",
+				 __func__);
 	}
 
 	/* Disable ep */
@@ -3894,21 +3906,27 @@ static void dwc2_hsotg_ep_stop_xfr(struct dwc2_hsotg *hsotg,
 		dev_warn(hsotg->dev,
 			 "%s: timeout DOEPCTL.EPDisable\n", __func__);
 
+	/* Clear EPDISBLD interrupt */
+	__orr32(hsotg->regs + epint_reg, DXEPINT_EPDISBLD);
+
 	if (hs_ep->dir_in) {
-		if (hsotg->dedicated_fifos) {
-			dwc2_writel(GRSTCTL_TXFNUM(hs_ep->fifo_index) |
-				GRSTCTL_TXFFLSH, hsotg->regs + GRSTCTL);
-			/* Wait for fifo flush */
-			if (dwc2_hsotg_wait_bit_set(hsotg, GRSTCTL,
-							GRSTCTL_TXFFLSH, 100))
-				dev_warn(hsotg->dev,
-					"%s: timeout flushing fifos\n",
-					__func__);
-		}
-		/* TODO: Flush shared tx fifo */
+		unsigned short fifo_index;
+
+		if (hsotg->dedicated_fifos || hs_ep->periodic)
+			fifo_index = hs_ep->fifo_index;
+		else
+			fifo_index = 0;
+
+		/* Flush TX FIFO */
+		dwc2_flush_tx_fifo(hsotg, fifo_index);
+
+		/* Clear Global In NP NAK in Shared FIFO for non periodic ep */
+		if (!hsotg->dedicated_fifos && !hs_ep->periodic)
+			__orr32(hsotg->regs + DCTL, DCTL_CGNPINNAK);
+
 	} else {
 		/* Remove global NAKs */
-		__bic32(hsotg->regs + DCTL, DCTL_SGOUTNAK);
+		__orr32(hsotg->regs + DCTL, DCTL_CGOUTNAK);
 	}
 }